If Hitler had never been born how would history differ?

Nobody knows, or can know.

Of course it would have been different.

First off there wouldn't have been that particular guy named Hitler. That alone would have altered zillions, even gazillions of existences.

Each and very thing which happens causes a ripple effect in and on every molecule and atom. Whatever he touched, even if he had not been power-mad and twisted, would have done its thing. If he had been a music star, that would have touched individuals causing actions by them which, because he wasn't a music star, did not happen.

For one thing, we would not have all those parodies on YouTube. Or would we? "Hitler hears he has never been born" - I'd like to see that.

The world would probably be backwards in technology. Seems it was wars that boosted science and technological progress. Maybe the US would never have gotten over the depression of the 1920's and 30's. We would still be driving carbureter cars with low gas mileage. Propeller airplanes and no internet.

I have seen this so often with abuse survivors, an almost tractor beam pull towards trying to figure out who they would be had the abuse not happened. It is a completely useless time suck at best, because we cant know the answer.

When Hitler ran for President against Hindenburg, he got his skinny butt whipped. Hindenburg was definitely the most popular public figure in Germany in 1933. Much of Hitler's gutter politics was borrowed from Ludendorff, who was uniformly unsuccessful. Ludendorff wsa responsible for the "statb in the back" myth and the "Versailles diktat" myth. Hitler was not actually able to make much political capital out of those claims--but in the West, people just eat up that old "Versailles diktat" crap. Ludendorff's claim in the "stab in the back" myth was that a victorious German army was betrayed by Marxists and
Bolsheviks. Although obviously untrue, it did give him a handle with right wing extremists, but it did not translate into political success. Hitler tried the same take after the Reichstag fire, blaming an unemployed Dutch bricklayer and communist. They then alleged that it was a part of a Comintern plot to undermine "democracy" in Germany (yeah, right, as though Hitler ever promoted democracy. The Comintern later alleged that the fire was in fact started by the SA, and was a Nazi false flag operation. Whatever the case, Hitler was able to pressure Hindenburg into banning left-wing parties.
Although the Nazis now seemed to have a better electoral opportunity, they still only polled fractionally less than 44% of the vote. The DNVP (German National Peoples' Party) had supported Hitler forthe office of Chancellor, and they now supported him in the Reichtag. Franz von Papen had been Chancellor briefly in 1932, and hoped to get the post again in 1933. But after Hindenburg was pressured into accepting Hitler, and the disappointing electoral results in 1933, he gave his support to Hitler. The NDSAP (the Nazis) and the DNVP then formed a "super majority" with the Zentrum, the Centre Party, the party of German Catholics. Together, these three parties passed the Enabling Act. This exploited a flaw in the Weimar constitution which was intended to give the Chancellor broad powers in time of national emergency. It allowed Hitler to legislate without reference to the Reigchstag. Of course, he used it to rid himself of political opposition.

This may all seem like so much hot air, but the point is that history is not necessarily deterministic. Some events may be inevitable, such as the revolution in France, but that doesn't mean the violence and upheaval are necessarily inevitable. The rise of Hitler and the NSDAP was not inevitable, and Germany starting another major European war was not inevitable. History might differ a good deal without different without Hitler.

Your mother and father would never have met.

The three guys you'd really want to shot through the head on the day they were born would be Muhammad, An Lushan, and Chuck Darwin. Hitler doesn't really compare to those three.

Nations and money would still exist, and therefore genocide would still happen

The one other person at the top of that list would be Rachel Carson.